Mouthing

In sign language, mouthing refers to the mouth movements that accompany manual signs, typically derived from the spoken language of the surrounding hearing community. For example, a signer using German Sign Language (DGS) may mouth the German word while simultaneously producing the sign. Mouthing serves important linguistic functions including disambiguating signs that share the same manual form, conveying grammatical information, and supporting comprehension. It is distinct from mouth gestures, which are non-speech-derived mouth movements that form part of the sign language itself. The quality and synchronisation of mouthing is a critical factor in the acceptability of sign language avatars and video-based sign language content.